The Large, Flat Chajnantor Plateau

Panoramic view of the ALMA Array Operation Site (AOS), located on the Chajnantor Plateau, at 5000 metres altitude on the Chilean Andes, near San Pedro de Atacama. This wide-angle view is taken from the east. On the right, toward the north and partially covered in snow, is the 5600-metre-high Cerro Chajnantor. Moving to the left, the APEX (Atacama Pathfinder Experiment) antenna is just visible on the horizon, followed by the 5300-metre-high Cerro Chico. At the centre of the image, toward the west, is the ALMA AOS Technical Building, which houses the correlator, an extremely powerful computer designed to combine the signal coming from the ALMA antennas. The antennas can be spread across the desert plateau over distances from 200 metres to 16 kilometres, which will give ALMA a powerful variable "zoom".